Multi-Mode Integrated Circuit Devices Including Mode Detection and Methods of Operating the Same

ABSTRACT

Multi-mode integrated circuit devices on an integrated circuit substrate include a controller configured to operate in a first mode compliant with the International Standard Organization (ISO) specification ISO 7816 and a second mode different from ISO 7816 responsive to a mode selection signal. A first plurality of input/output pads are associated with operations in the first mode and a second plurality of input/output pads are associated with operations in the second mode. A mode detector circuit is coupled to at least one of the second plurality of input/output pads and configured to detect connection of the at least one of the second plurality of input/output pads to an external device and to activate the mode selection signal to select the second mode responsive to detection of connection of the at least one of the second plurality of input/output pads to the external device.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.11/036,735, filed on Jan. 14, 2005, which claims priority from KoreanPatent Application No. 2004-0052078, filed on Jul. 5, 2004, thedisclosures of which are hereby incorporated herein by reference intheir entirety.

BACKGROUND OF THE INVENTION

The present invention relates to integrated circuit devices and, moreparticularly, to multi-mode integrated circuit devices and methods ofoperating the same.

Smart cards (SC) are typically plastic cards having an embeddedintegrated circuit (IC). The integrated circuit may be, for example, alogic circuit with its associated memories or a microcontroller with itsassociated memories and software coupled to a custom integrated circuitblock. The integrated circuit of a smart card is typically attached to alead frame and wire-bonding techniques are used to connect paths of theintegrated circuit to lead frame contacts. Potting and otherstrengthening methods may be used to protect the integrated circuitagainst chemical and mechanical stresses and the like. Contact pads aretypically located on one side of the smart card and are provided in alimited, specified number, such as eight. The contact pads are typicallyutilized to perform transactions with a smart card reader using a serialprotocol.

Various standards for smart cards are published by the InternationalStandards Organization (ISO). The ISO 7816 standards have allowedextensive use of smart cards in a variety of applications, such asaccounting, cryptography, personal authentication, and execution of JAVAscripts. ISO documents ISO 7816-1 Physical Characteristics, ISO 7816-2Dimensions and Locations of contacts, ISO 7816-3 Electronic signals andtransmission protocols and ISO 7816-10 Electronic signals and answer toreset for synchronous cards are included in the ISO 7816 standards forsmart card operation.

Smart cards are used in a variety of different applications, such ascellular telephone, credit card and identification card applicationsutilizing authentication and/or security. For example, it is known touse authenticated smart cards in connection with prepaid cards in publictelephony, for bankcards in Point of Sale (POS) terminals and AutomaticTeller Machines (ATM), for pay TV providers in set top boxes and forwireless telecommunications operators, for example, in a subscriberidentification module (SIM) used in the Global System for Mobilecommunications (GSM) terminals.

Smart cards typically perform communication transactions with the hostthrough a smart card reader. For example, a personal computer system 100is illustrated in FIG. 1 that is configured to read from a smart card.The personal computer system 100 includes a processor or host unit 110,a display 120 and a keyboard 130. Also shown in the system 100 in FIG. 1is a mouse 140 and a smart card reader 150. The display 120, keyboard130, mouse 140 and smart card reader 150 are coupled, either by cablesand/or by wireless link, to the host unit 110. The smart card reader 150communicates with a smart card 160 using a first protocol and with thehost unit 110 using a second protocol. The first protocol is typicallythe ISO 7816 protocol discussed above complying with InternationalStandard Organization (ISO) standards. The smart card reader 150 may becoupled to the host unit 110 by a serial port, parallel port, or thelike using the second distinct protocol. The smart card 160 may be read,for example, in connection with secure transactions over the internetaccessed using the personal computer system 100.

The card reader 150 typically contains electronic circuits and embeddedsoftware that enable communication with the smart card 160 using the ISO7816 protocol and the host unit 110 using a serial protocol, such as anRS 232C protocol, through a serial port of the host unit 110. For aserial link, such as an RS 232C protocol serial link, between the smartcard reader 150 and the host unit 110, a variety of communication ratesmay be supported, such as a base rate of 9600 bits per second (bps) oroptional higher rates, such as two or four times the base rate. Anoverall data transmission speed between the smart card 160 and the hostunit 110 may be limited because of the serial port low speed data ratefor data transfer, which is typically below 1 Megabits per second(Mbps). As such, the reader 150 may need to read data from the smartcard 160 and transmit the data to the host unit 110 of the personalcomputer system 100 after first buffering the data.

An alternative approach to reading smart card information is illustratedfor the personal computer system 200 in FIG. 2. The personal computersystem 200 includes a host unit 210 having the ability to supportcommunications not only through a serial RS 232C type port but alsothrough a Universal Serial Bus (USB) protocol port and/or an Instituteof Electrical and Electronics Engineers (IEEE) 1394 protocol port. Thesmart card device 160′ may communicate with the host using USB and/orIEEE 1394 protocols through a dongle 250. The dongle 250 is,essentially, little more than a connector socket with a plug 251configured to connect to a USB or IEEE port of the host unit 110 using acable or wireless connection. As such, a different dongle 250configuration having a different connector 251 may be utilized dependingupon whether USB or IEEE 1394 communications are to be used. The hostunit 210 further is coupled to a display 220, keyboard 230 and mouse 240to support user input/output communications.

Note that the smart card 160′ of FIG. 2 is illustrated as includingconnectors (contact pads) 261 on an upper face thereof and the smartcard 160 shown in FIG. 1 is illustrated with connectors 161 on an upperface thereof. The connectors 161, 261 may be utilized to enableinput/output communications between the smart card 160, 160′ and therespective smart card reader 150 or dongle 250.

It will be understood that the smart card 160 differs from the smartcard 160′ in that the smart card 160 is configured and specificallyprovided for reading in an ISO standard smart card reader 150 while thesmart card 160′ is configured to communicate with a USB protocol whenthe dongle 250 is configured for a USB interface 251 and a distinctdifferent smart card is provided for reading by an IEEE 1394 dongle 250with an IEEE 1394 connector 251. In other words, smart card 160typically may not be read by the dongle 250 and the smart card 160′typically may be not read by the smart card reader 150.

By using a USB or IEEE 1394 interface, as with the personal computersystem 200, a higher data transfer rate from the smart card 160′ may beprovided. For example, a USB interface typically supports a datacommunication rate of 12 Mbps or more and an IEEE 1394 interfacetypically supports a data communication rate of about 400 Mbps. As such,direct data transfer may be provided from the smart card 160′ to thehost unit 210 without utilizing buffering or the like in the dongle 250,therefore simplifying the dongle 250. In addition, hot plug and playcapability may be provided without disrupting the personal computersystem 200 when a smart card 160′ is inserted into the dongle 250.

The USB interface can generally be described as a set of four wires ofwhich two carry a power supply (VDD, VSS) and two other wires supportdata (D+, D−). The USB standard is defined by the Universal Serial BusSpecification written and controlled by USB Implementers Form Inc., anon-profit corporation founded by the group of companies that developedthe USB specification.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide multi-mode integratedcircuit devices on an integrated circuit substrate that include acontroller configured to operate in a first mode compliant with theInternational Standard Organization (ISO) specification ISO 7816 and asecond mode different from ISO 7816 responsive to a mode selectionsignal. A first plurality of input/output pads is associated withoperations in the first mode and a second plurality of input/output padsis associated with operations in the second mode. A mode detectorcircuit is coupled to at least one of the second plurality ofinput/output pads and configured to detect connection of the at leastone of the second plurality of input/output pads to an external deviceand to activate the mode selection signal to select the second moderesponsive to detection of connection of the at least one of the secondplurality of input/output pads to the external device. The second modemay be an Institute for Electrical and Electronic Engineers (IEEE) 1394protocol mode or a Universal Serial Bus (USB) protocol mode.

In further embodiments of the present invention, the controller isconfigured to generate a mode detection sample signal and the modedetector circuit is configured to activate the mode selection signalresponsive to detection of connection of the at least one of the secondplurality of input/output pads to an external device at a plurality ofsequential times spaced at an interval defined by the mode detectionsample signal. The mode detector circuit may be configured to detect anelectrical characteristic, such as a resistance, of an external deviceconnected to the at least one of the plurality of input/output pads. Themode detector circuit may be configured to activate the mode selectionsignal responsive to the electrical characteristic having a detectedlevel between a first predetermined level and a second predeterminedlevel.

In other embodiments of the present invention, the mode detector circuithas an active mode in which it is configured to detect connection of theat least one of the second plurality of input/output connectors to anexternal device and a power save mode. In the power save mode, the modedetector circuit may be disconnected from the at least one of the secondplurality of input/output pads. The controller may be configured todisconnect the mode detector circuit from the at least one of the secondplurality of input/output pads in the second mode.

In further embodiments of the present invention, the mode detectorcircuit includes a reference current generator circuit coupled to the atleast one of the second plurality of input/output pads and a connectiondetect circuit coupled to the reference current generator circuit and tothe at least one of the second plurality of input/output pads thatactivates the mode selection signal responsive to a detection outputsignal from the reference current generator circuit and to a signal onthe at least one of the second plurality of input/output pads. Areference voltage generator circuit may also be included that outputs areference voltage to the reference current generator circuit and to theconnection detect circuit and the connection detect circuit may activatethe mode selection signal responsive to the reference voltage, theoutput signal from the reference current generator circuit and thesignal on the at least one of the second plurality of input/output pads.The controller may be configured to generate a switch signal in thesecond mode and the mode detector circuit may include a switch circuitthat disconnects the mode detector circuit from the at least one of thesecond plurality of input/output pads responsive to the switch signal.

In yet other embodiments of the present invention, the reference currentgenerator circuit includes first and second current source transistors,the current source transistors having current mirror characteristics,the second current source transistor having an output coupled to a firstinput of the connection detect circuit and to the at least one of thesecond plurality of input/output pads. A first resistor has a first nodecoupled to an output of the first current source transistor and to asecond input of the connection detect circuit. A second resistor has afirst node coupled in series to a second node of the first resistor. Theconnection detect circuit is configured to activate the mode selectionsignal responsive to a voltage at the first input of the detectorcircuit and a voltage at the second input to the connection detectcircuit to select the second mode when the resistance of the externaldevice coupled to the at least one of the second plurality ofinput/output pads is greater than a resistance of the second resistorand less than a sum of resistances the first and second resistor.

In further embodiments of the present invention, the controller isconfigured to generate a mode detection sample signal and the modedetector circuit is configured to activate the mode selection signalresponsive to detection of connection of the at least one of the secondplurality of input/output pads to an external device at a plurality ofsequential times spaced at an interval defined by the mode detectionsample signal. The mode detector circuit includes a shift registercircuit clocked by the mode detection sample signal that activates themode selection signal after detecting connection of the at least one ofthe second plurality of input/output pads to an external device at aplurality of sequential times spaced at an interval defined by the modedetection sample signal.

In yet further embodiments of the present invention, the referencecurrent generator circuit includes an amplifier having a first inputcoupled to the reference voltage signal from the reference voltagesignal generator, a second input coupled to the first node of the secondresistor and an output coupled to gates of the first and second currentsource transistors. A system bus may be coupled to the controller and anISO interface circuit and second mode interface circuit and a memory maybe coupled to the system bus. The memory may be multiple memoriesincluding a random access memory (RAM) coupled to the system bus, anon-volatile memory (NVM) coupled to the system bus and a read onlymemory (ROM) coupled to the system bus.

A smart card system may be provided including a USB adapter module and amulti-mode device as described for various embodiments of the presentinvention above.

In yet other embodiments of the present invention, a multi-modeintegrated circuit device on an integrated circuit substrate includes acontroller configured to operate in a first mode compliant with theInternational Standard Organization (ISO) specification ISO 7816protocol and a second mode different from ISO 7816 responsive to a modeselection signal. A first plurality of input/output pads is associatedwith operations in the first mode and a second plurality of input/outputpads is associated with operations in the second mode. A mode detectorcircuit coupled to at least one of the second plurality of input/outputpads is configured to detect a resistance level of an external deviceconnected to the at least one of the second plurality of input/outputpads and to activate the mode selection signal to select the second moderesponsive to detection of a resistance level of the external devicebetween a first predetermined level and second predetermined level.

In further embodiments of the present invention, the controller isfurther configured to operate in a third mode compliant with anInstitute for Electrical and Electronic Engineers (IEEE) 1394 protocolresponsive to the mode selection signal and the mode detector circuit isconfigured to generate a first value of the mode selection signalresponsive to detection of connection of the at least one of the secondplurality of input/output pads to a USB external device and to generatea second value of the mode selection signal responsive to detection ofconnection of the at least one of the second plurality of input/outputpads to an IEEE 1394 device.

In other embodiments of the present invention, a multi-mode integratedcircuit device on an integrated circuit substrate includes a controllerconfigured to operate in a first mode compliant with the InternationalStandard Organization (ISO) specification ISO 7816 protocol and a secondmode different from ISO 7816 responsive to a mode selection signal andto generate a mode detection sample signal. A first plurality ofinput/output pads is associated with operations in the first mode and asecond plurality of input/output pads is associated with operations inthe second mode. A mode detector circuit coupled to at least one of thefirst plurality or the second plurality of input/output pads isconfigured to detect connection of the at least one of the firstplurality of input/output pads or the at least one of the secondplurality of input/output connectors to an external device at aplurality of sequential times spaced at an interval defined by the modedetection sample signal and to drive the mode selection signal to selectthe first mode or the second mode responsive to detection of connectionof the at least one of the first plurality of input/output pads or theat least one of the second plurality of input/output pads to theexternal device at the plurality of sequential times.

The mode detector circuit may be configured to detect connection of theat least one of the first plurality of input/output pads or the at leastone of the second plurality of input/output connectors to an externaldevice by detecting an electrical characteristic of an external deviceconnected to the at least one of the first plurality of input/outputpads or the at least one of the second plurality of input/output pads toan external device. The mode detector circuit may be configured toactivate the mode selection signal responsive to the electricalcharacteristic having a detected level between a first predeterminedlevel and a second predetermined level. The controller may be configuredto disconnect the mode detector circuit from the second plurality ofinput/output pads in the second mode.

In further embodiments of the present invention, the mode detectorcircuit includes a reference current generator circuit coupled to the atleast one of the second plurality of input/output pads and a comectiondetect circuit coupled to the reference current generator circuit thatactivates the mode selection signal responsive to a detection outputsignal from the reference current generator circuit. A reference voltagegenerator circuit may also be provided that outputs a reference voltageto the reference current generator circuit and to the connection detectcircuit and the connection detect circuit may activate the modeselection signal responsive to the reference voltage and the outputsignal from the reference current generator circuit. The controller maybe configured to generate a switch signal in the second mode and themode detector circuit may include a switch circuit that disconnects themode detector circuit from the second plurality of input/outputconnectors responsive to the switch signal.

In other embodiments of the present invention, the mode detector circuitfurther includes a shift register circuit clocked by the mode detectionsample signal that activates the mode selection signal after detectingconnection of the at least one of the second plurality of input/outputpads to an external device at a plurality of sequential times spaced atan interval defined by the mode detection sample signal. The referencecurrent generator circuit may further include an amplifier having afirst input coupled to the reference voltage signal from the referencevoltage signal generator, a second input coupled to the first node ofthe second resistor and an output coupled to gates of the first andsecond current source transistors.

In yet further embodiments of the present invention, methods forselection of an operating mode for a multi-mode integrated circuit smartcard device configured to operate in a first mode compliant with theInternational Standard Organization (ISO) specification ISO 7816 and asecond mode different from ISO 7816 include detecting connection of aninput/output connector of the device associated with the second mode toan external device. A mode selection signal is activated responsive todetecting connection of the input/output connector of the deviceassociated with the second mode to an external device. The device isoperated in the second mode responsive to activation of the modeselection signal and may be operated in the first mode when the modeselection signal is not activated.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to theembodiments illustrated in the attached drawings in which:

FIG. 1 is a schematic diagram illustrating a computer system including asmart card interface device according to the prior art.

FIG. 2 is a schematic diagram illustrating a computer system includinganother smart card interface device according to the prior art.

FIG. 3 is a block diagram illustrating a multi-mode integrated circuitdevice according to some embodiments of the present invention.

FIG. 4 is a block diagram illustrating a mode detector circuit accordingto some embodiments of the present invention.

FIG. 5 is a flowchart illustrating operations for selecting an operatingmode of a multi-mode integrated circuit device according to someembodiments of the present invention.

FIG. 6 is a timing diagram illustrating operations of a multi-modeintegrated circuit device according to some embodiments of the presentinvention.

FIG. 7 is a flowchart illustrating operations for selecting an operatingmode of a multi-mode integrated circuit device according to someembodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the inventionto those skilled in the art.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. Like numbers refer to likeelements throughout. Signals may also be synchronized and/or undergominor Boolean operations (e.g., inversion) without being considereddifferent signals. As used herein, the term “and/or” includes any andall combinations of one or more of the associated listed items.

It will be understood that, although the tenns first, second, etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother region, layer or section. Thus, a first element, component,region, layer or section discussed below could be termed a secondelement, component, region, layer or section without departing from theteachings of the present invention.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs. It will befurther understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined herein.

Various embodiments of the present invention will now be described withreference to FIGS. 3 through 7. FIG. 3 is a block diagram illustrating amulti-mode integrated circuit device on an integrated circuit(semiconductor) substrate according various embodiments of the presentinvention. The multi-mode integrated circuit (smart card) device 260includes a microprocessor or controller 350 that is configured tooperate in a first mode, compliant with the International StandardOrganization (ISO) specification ISO-7816 and a second mode, differentfrom ISO 7816 (illustrated as a USB mode) responsive to a mode selectionsignal USB_MODE. In particular, FIG. 3 illustrates a circuit diagram fora smart card including an ISO interface (IF) 310 and a USB interfacecircuit 360. The multi-mode integrated circuit (smart card) device 260includes a plurality of contact pads including voltage inputs VDD 301and VSS 302 and an ISO input/output (I/O) contact pad 303. The USBinput/output pads include a contact pad 304 corresponding to the USB D+signal and contact pad 305 corresponding to the USB D− signal. Also showin the embodiments of FIG. 3 are a clock (CLK) contact pad 306 and areset (RST) contact pad 307.

While the multi-mode integrated circuit (smart card) device 260 supportsboth ISO 7816 and USB communications for the embodiments of the presentinvention illustrated in FIG. 3, it will be understood that furtherembodiments of the present invention include an IEEE 1394 interfacecircuit instead of and/or in addition to the USB interface circuit 360.For an IEEE 1394 interface, four additional contact pads will generallybe provided corresponding to the signals TPA, ˜TPA, TPB, ˜TPB. In suchembodiments, the multi-mode integrated circuit (smart card) device 260may selectively operate in one of several non-ISO modes or in an ISOmode.

Also shown in the embodiments of FIG. 3 is a mode detector circuit 370that is coupled to one of the input/output contact pads 304, 305associated with the USB interface circuit 360. The mode detector circuit370 is configured to detect connection of a contact pad 304, 305 to anexternal device and to active the mode selection signal USB_MODE toselect the USB mode responsive to detection of connection of a contactpad 304, 305 to an external device. The detection of connection of themulti-mode integrated circuit (smart card) device 260 to a non-ISO portof an external host using one of the contact pads 304, 305 may occur,for example, during a power-up sequence of the multi-mode integratedcircuit (smart card) device 260.

As further illustrated in FIG. 3, the multi-mode integrated circuit(smart card) device 260 includes a system bus 308 coupled to thecontroller 350. In addition, the ISO interface circuit 310 and the USBinterface circuit 360 are also connected to the system bus 308. For theembodiments illustrated in FIG. 3, a plurality of different memories arealso coupled to the controller 350 over the system bus 308, including arandom access memory (RAM) 320, a non-volatile memory (NVM) 330 and aread-only memory (ROM) 340. The USB interface contact pads 304, 305 maybe coupled through a USB adaptor module to provide a smart card systemincluding the multi-mode integrated circuit (smart card) device 260 ofFIG. 3. Such a USB interface is illustrated, for example, in FIG. 2 asUSB plug 251.

In the illustrated embodiments of FIG. 3, the mode detector circuit 370includes a reference voltage generator circuit 371, a reference currentgenerator circuit 372, a connection detect circuit 373, a switch circuit374 and a USB mode signal generator circuit 376. The mode detectorcircuit 370 is configured to detect an electrical characteristic of anexternal device connected to the USB D+contact pad 304 in theillustrated embodiments of FIG. 3. However, it will be understood that,in other embodiments of the present invention, the mode detector circuit370 may be configured and coupled to detect electrical characteristicson contact pad 305 or another of a plurality of contact pads associatedwith the non-ISO mode of the multi-mode integrated circuit (smart card)device 260. For the illustrated embodiments of FIG. 3, the mode detectorcircuit 370 is configured to activate the mode selection USB_MODEresponsive to an electrical characteristic having a detected levelbetween a first predetermined level and a second predetermined level aswill be further discussed with reference to FIG. 4, which illustratesembodiments where the electrical characteristic is a resistance.

As shown in the embodiments of FIG. 3, the mode detector circuit 370 maybe disconnected from the contact pad 304 by the switch circuit 374responsive to a switch signal SW1 from the controller 350. As such, themode detector circuit 370 may have an active mode, in which it isconfigured to detect connection of the contact pad 304 to an externaldevice, and a power save mode where the mode detector circuit isdisconnected from the contact pad 304. Thus the switch signal SW1 isprovided to the switch circuit 374 to disconnect the mode detectorcircuit 370 from one or more input/output pads associated with thenon-ISO mode of operation of the multi-mode integrated circuit (smartcard) device 260.

For the embodiments of FIG. 3, the reference voltage generator circuit371 outputs a reference voltage to the reference current generatorcircuit 372 and to the connection detect circuit 373. The connectiondetect circuit is also coupled through the switch circuit 374 to thecontact pad 304 and to an output signal from the reference voltagegenerator circuit 371. The connection detect circuit 373 activates thedetection output signal UDET responsive to the reference voltage fromthe reference voltage generator circuit 371, a signal level from thecontact pad 304 connection and the output signal from the referencecurrent generator circuit 372. The reference current generator circuit372 is also coupled to the input/output contact pad 304 used for the USBmode of the multi-mode integrated circuit (smart card) device 260.

As will be further described with reference to FIG. 4, the referencecurrent generator circuit 372 generates a reference current responsiveto the input reference voltage signal from the reference voltagegenerator 371 and supplies the input/output contact pad 304 with thecurrent when the switch 374 is closed responsive to the switching signalSW1. For the configuration shown in FIG. 3, the connection detectcircuit 373 sets UDET to an active state (logic high) when the referencecurrent is discharged through the contact pad 304 at a predefined levelindicating that the D+contact pad 304 is connected to a non-ISO pad of ahost device. In other words, when a USB communication interface isavailable for communication from the multi-mode integrated circuit(smart card) device 260 to a USB host, the USB mode may be selected.

The mode signal generator circuit 376 for the illustrated embodiments ofFIG. 3 sets USB_MODE to an active state (logic high) when UDET is set toan active state a predetermined number of times as will be furtherdescribed with reference to FIG. 4. More particulary, the mode signalgenerator circuit 376 activates the USB_MODE signal responsive to UDETbased on the mode detection sample signal GETDT from the controller 350.

For the embodiments illustrated in FIG. 3, if the USB_MODE signal isinactive, the multi-mode integrated circuit (smart card) device 260operates in the ISO mode. In the ISO mode, the D+ and D− pads 304, 305may be disabled. When the USB_MODE signal is active, the multi-modeintegrated circuit (smart card) device 260 operates in a non-ISO (USBshown in FIG. 3) mode. In the non-ISO mode, the contact pads associatedwith ISO operation, including the I/O contact pad 303, the CLK contactpad 306 and the RST contact pad 307 may be disabled.

Referring now to FIG. 4, a mode detector circuit 370 according tovarious embodiments of the present invention will now be furtherdescribed. As shown in the embodiments of FIG. 4, the mode detectorcircuit 370 is coupled to a USB host device 210. The USB contact pads211 of the host device 210 shown in FIG. 4 include a voltage source VDDcontact pad 212, voltage ground reference VSS contact pad 213, a D−contact pad 214 and a D+contact pad 215. The D− contact pad 214 and theD+contact pad 215 are coupled to a host USB interface circuit 216. Inaddition, the D− contact pad 214 is coupled through a pull-down resistorRPD1 to a ground reference and the D+contact pad 215 is coupled througha pull-down resistor RPD2 to the ground reference. The contact pad 215is coupled to the contact pad 304 of the mode detector circuit 370.

The reference voltage generator 371 of the mode detector circuit 370 isconnected to the PDW signal from the controller 350 and outputs avoltage reference signal VREF to the reference current generator circuit372 and to the connection detect circuit 373. The reference currentgenerator circuit 372 includes an operational amplifier 401, two MOSFETtransistors MP1, MP2 and two resistors R1, R2. The MOSFET transistorsMP1, MP2 for the illustrated embodiments of FIG. 4 are selected to havethe same voltage from gate to source (V_(gs)) and are connected to actas a current mirror circuit. In other words, the current I through thetransistor MP1 and the current I through the transistor MP2 aresubstantially the same when current is flowing through transistor MP2(note that when the switch circuit 374 is open or no external device isconnected to contact pad 304 substantially no current would be expectedto flow through transistor MP2).

An output voltage from the operational amplifier 401 is coupled to thegates of the transistors MP1 and MP2. A voltage level V1 between theresistors R1 and R2 is fed back as an input to the operational amplifier401. Accordingly, the voltage level V1 rises to the voltage referenceVREF level through the operational amplifier 401 and the transistor MP1.As the current through the transistor MP1 is equal to V1 (=VREF)/R2, thevoltage level V2 equals VREF (1+R1/R2)). In other words, resistors R1and R2 operate as a voltage divider circuit with the voltage between R1and R2 (V1) being set to VREF.

As discussed with reference to the embodiments of FIG. 3, a switchcircuit 374 may be turned on in response to a switching signal SW1 fromthe controller 350 to activate a mode detection active mode of the modedetector circuit 370. In the active mode, with the switch 374 closed,the detection output signal voltage V3 from the reference currentgenerator 372 will be at the source voltage reference level VDD input tothe transistors MP1, MP2 when the D+contact pad 304 is not connected toa D+contact pad 215 of a host and is, instead, an open circuit. However,if the D+contact pad 304 is connected to the D+contact pad 215 of a host210, the detection output signal voltage V3 is lowered due to dischargeof current through the pull down resistor RPD2 in the host 210.

The connection detect circuit 373 includes operational amplifiers 403,404 and an AND gate 405. An input of each of the operational amplifiers403, 404 is coupled to the detection output signal having a voltage V3from the reference current generator circuit 372. A second input of theoperational amplifier 403 is coupled to the resistor R1 at the V2voltage level. A second input of the operational amplifier 404 iscoupled to the D+contact pad 304. The outputs of the operationalamplifiers 403 and 404 are coupled to the AND gate 405, which outputsthe mode detect signal UDET.

The connection detect circuit 373 sets UDET to an active state (level)when the detection output signal voltage V3 is higher than the referencevoltage VREF and is also lower than the voltage level V2. In someembodiments of the present invention, the voltage level V2 may be set tobe about twice the reference voltage VREF. In particular embodiments ofthe present invention, the reference voltage VREF is 1.2 volts, thesource voltage VDD is 3.3 volts, the resistor R1 is 10 kiloohms (kΩ),the resistor R2 is also 10 kΩ and the pull-down resistors RPD1 and RPD2are 15 kΩ. As a result, when connected to a host device 210, a 15 kΩresistor is positioned between the voltage reference V3 and the groundreference, a 10 kΩ resistance R2 is positioned between the voltagereference V1 and a ground reference and a 20 kΩ resistance (R1+R2) ispositioned between the voltage reference V2 and the ground reference. Assuch, with the current substantially the same through both of thetransistors MP1 and MP2, the detector output signal voltage V3 will fallsubstantially at a midpoint between the voltage references V2 and V1.

The connection detect circuit 373 detects the voltage level V2 beinggreater than V3 using the operational amplifier 403 and detects thedetection output signal voltage level V3 being greater than thereference voltage level VREF, which equals the voltage reference levelV1, using the operational amplifier 404. When both conditions are true,the AND gate 405 sets UDET to an active (logic high) state.

The output UDET from the connection detect circuit 373 is fed to themode signal generator circuit 376. The mode signal generator circuit 376is configured to activate the mode selection signal USB_MODE responsiveto detection of connection of the contact pad 304 to an external hostdevice 210, a plurality of sequential times spaced at an intervaldefined by the mode detection sample signal GETDT.

The mode detection sample signal GETDT is generated by the controller350 as illustrated in FIG. 3. In particular embodiments of the modesignal generator circuit 376 shown in FIG. 4, the USB_MODE signal is setto an active state when the mode signal generator circuit 376 receivesthe signal UDET in the activated state three times in a row within adetermined time period set by the clocking rate of the sample signalGETDT. The three sequential detections of UDET in an active state areprovided by the use of three flip-flops 410, 411, 412, each of which isclocked by the sample signal GETDT. The signal UDET is fed into a firstof the flip-flops 410 with an output thereof coupled to the input of thenext flip-flop 411 as well as to an AND gate 413. The output of thesecond flip-flop 411 is fed to an input of the third flip-flop 412 aswell as to an input of the AND gate 413. Finally the output of the thirdflip-flop 412 is also fed to the AND gate 413. As a result, the outputsignal USB_MODE is set to a high active state when UDET is clocked threesequential times at an active state through the flip-flop circuits 410,411, 412. In some embodiments of the present invention, use of modesignal generator circuit 375 may reduce the risk of or prevent erroneousdetection of UDET caused by human interface interactions, such as when asmart card connector is inserted into a host connector or removedtherefrom.

After determining the interface mode of the multi-mode integratedcircuit (smart card) device 260 and setting the signal USB_MODE, currentfeed to the mode detector circuit 370 may be cut off. In addition, theswitch circuit 374 may be opened. For example, current to the modedetector circuit 370 may be cut off responsive to the PDW signaldescribed above to reduce power consumption by the mode detector circuit370 in addition to opening of the switch circuit 374.

To summarize, as illustrated by the embodiments of the present inventionshown in FIG. 4, a reference current generator circuit 372 may include afirst MP1 and second MP2 current source transistors having currentmirror characteristics. The second current source transistor MP2 has anoutput coupled to a first input of the connection detect circuit 373 andto the contact pad 304 through the switch circuit 374. A first resistorR1 has a first node coupled to an output of the first current sourcetransistor MP1 and to second input of the connection detect circuit 373.A second resistor R2 has a first node coupled in series to an additionalnode of the first resistor R1. With this arrangement, the connectiondetect circuit 373 is configured to activate the mode selection signalUSB_MODE responsive to a detection output signal voltage V3 at a firstinput of the connection detect circuit 373 and a voltage V2 at a secondinput to the connection detect circuit 373 to detect the non-ISOoperating mode when the resistance of the external device 210 coupled tothe contact pad 304 is greater than the second resistor R2 and less thana sum of the first R1 and second R2 resistor. The shift register circuitof the mode signal generator circuit 376, including the plurality offlip-flops 410, 411, 412 and the AND gate 413, clocked by the modedetection signal GETDT, activates the mode selection signal USB_MODEafter detecting connection of the contact pad 304 to the external hostdevice 210 at a plurality of sequential times set by the sample signalGETDT. The mode detection signal USB_MODE may thereby be activatedresponsive to detection of a resistance level of the external hostdevice 210 between a first predetermined level and a secondpredetermined level established by selection of the resistor values R1,R2 relative to the resistance characteristic of the pull down resistorRPD2 of the host device 210.

While described above to simplify understanding of various embodimentsof the present invention with reference to a two mode multi-modeintegrated circuit device where the second mode (or non-ISO mode) is aUSB mode, it will be understood, as discussed previously, that themulti-mode device may be an ISO and IEEE multi-mode device. In addition,a third mode may be added to the embodiments as described above so as tooperate in a third mode compliant with an Institute for Electrical andElectronic Engineers (IEEE)1394 protocol responsive to a mode detectionsignal. In such instances, the mode detector circuit 370 may beconfigured to generate a first value (USB_MODE) of the mode detectionsignal responsive to detection of connection of a contact pad to a USBexternal device and to generate a second value (IEEE_MODE) of the modedetection signal responsive to detection of connection of a non-ISOcontact pad to an IEEE 1394 host device. It will be further understoodthat, in such embodiments, the circuitry described above for detectionof a resistance value characteristic of an external device may beduplicated for detection of connection of an external IEEE 1394 devicewith the resistance values of the resistors R1, R2 selected to providedetection of the corresponding load resistance of an IEEE 1394 hostdevice 210. It will be further understood that the electricalcharacteristic detected at the connection need not be a resistance andmay be, for example, a capacitance, inductance, impendance or the like,and that different driving signals coupled through a switch circuit 374for testing such other electrical characteristics may be incorporated infurther embodiments of the present invention.

Operations for mode selection of a multi-mode integrated circuit smartcard device according to various embodiments of the present inventionwill now be described with reference to the flowchart diagram of FIG. 5.As shown in the embodiments of FIG. 5, after insertion of the smart cardintegrated circuit device into a host device reader, a power-on sequencefor the smart card integrated circuit device commences (Block 501).Active mode for the mode detection circuit is then initiated by turningon the switch circuit 374 (Block 503) following a power-on sequence atBlock 501 that may include activating the signal PDW to power upadditional circuitry within the mode detector circuit 370. After turningon the switch circuit 374, if the voltage V3 is greater than thereference voltage VREF and less than the voltage V2 (Block 505), thedetection signal UDET is generated at an active state (Block 507). IfUDET is detected as active a predetermined number of times (Block 509),the mode detect signal is generated (Block 511). When the USB_MODEsignal is active, non-ISO operations are initiated (Block 513).Operations at Block 513 may include enabling the non-ISO interfacecontact pads and disabling the ISO interface contact pads.

When the voltage V3 is less than the reference voltage VREF or when thevoltage V3 is greater than the voltage V2 (Block 505), the detectionsignal is generated as UDET inactive (Block 507). ISO-mode operationsare then initiated (Block 515). Operations at Block 515 may includeenabling the ISO interface contact pads and disabling the non-ISOinterface contact pads and circuitry. The CPU/controller operations areinitiated (Block 517). As shown in FIG. 5, for some embodiments of thepresent invention, a power-down mode for the mode detection circuit maythen be generated, for example, by activating the signal PDW for theembodiments illustrated in FIGS. 3 and 4 (Block 519).

Timing operations relating to some embodiments of the present inventionare illustrated in FIG. 6, where the signals SW1, D+, UDET, GETDT andUSB_MODE correspond to the signal notation shown in the embodiments ofFIG. 3. Note that, for the illustrated embodiments of FIG. 6, connectionof an external circuit to the contact pad for the D+ signal must bedetected three sequential times before the USB_MODE signal is generated,with the GETDT signal clocking detection of connection of the externaldevice at three sequential times to set the USB_MODE signal. As alsoshown in FIG. 6, in some embodiments of the present invention, theswitch signal SW1 is not maintained on throughout the sequence ofmultiple samples of GETDT, but is instead only activated duringrespective sample windows. Such intermittent timed operations may reducethe power consumption of the mode detector circuit 370.

Methods for selection of an operating mode for a multi-mode integratedcircuit smart card device configured to operate in a first modecompliant with the International Standard Organization (ISO)specification ISO 7816 and in a second mode, different from ISO 7816,according to some embodiments of the present invention will now bedescribed with reference to FIG. 7. As shown in FIG. 7, connection of aninput/output connector of the device associated with the second mode toan external device is detected (Block 700). A mode selection signal isactivated responsive to detecting connection of the input/outputconnector of the device associated with the second mode to an externaldevice (Block 705). If a connection to an external device on aninput/output connector associated with the second mode is detected(Block 710), operation in the second mode is initiated (Block 720). Ifan external device is not connected to an input/output connectorassociated with the second mode (Block 710), operations in the first (orISO 7816 compliant) mode is selected (Block 715).

It will be noted that, in some alternate implementations, thefunctions/acts noted in the blocks of FIGS. 5 and 7 may occur out of theorder noted in the flowchart. For example, two blocks shown insuccession may, in fact, be executed substantially concurrently, or theblocks may sometimes be executed in the reverse order, depending uponthe functionality/acts involved.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. In the claims, means-plus-function clauses are intended tocover the structures described herein as performing the recited functionand not only structural equivalents but also equivalent structures.Therefore, it is to be understood that the foregoing is illustrative ofthe present invention and is not to be construed as limited to thespecific embodiments disclosed, and that modifications to the disclosedembodiments, as well as other embodiments, are intended to be includedwithin the scope of the appended claims. The invention is defined by thefollowing claims, with equivalents of the claims to be included therein.

1. A multi-mode integrated circuit device, comprising: a controllerconfigured to operate in a first mode compliant with the InternationalStandard Organization (ISO) specification ISO 7816 and a second modedifferent from ISO 7816 responsive to a mode selection signal; a firstplurality of input/output pads associated with operations in the firstmode; a second plurality of input/output pads associated with operationsin the second mode, the second plurality of input/output pads includinga first voltage input/output pad, a second voltage input/output pad anda data input/output pad configured for a cable connection to communicatewith an external device; and a mode detector circuit coupled to at leastone of the second plurality of input/output pads and configured todetect connection of the at least one of the second plurality ofinput/output pads to the external device and to activate the modeselection signal to select the second mode responsive to detection ofconnection of the at least one of the second plurality of input/outputpads to the external device.
 2. The multi-mode integrated circuit deviceof claim 1 wherein the second mode comprises an Institute for Electricaland Electronic Engineers (IEEE) 1394 protocol mode or a Universal SerialBus (USB) protocol mode.
 3. The multi-mode device of claim 1 wherein thecontroller is configured to generate a mode detection sample signal andwherein the mode detector circuit is configured to activate the modeselection signal responsive to detection of connection of the at leastone of the second plurality of input/output pads to an external deviceat a plurality of sequential times spaced at an interval defined by themode detection sample signal.
 4. The multi-mode device of claim 1wherein the mode detector circuit is configured to detect an electricalcharacteristic of an external device connected to the at least one ofthe plurality of input/output pads.
 5. The multi-mode device of claim 4wherein the mode detector circuit is configured to activate the modeselection signal responsive to the electrical characteristic having adetected level between a first predetermined level and a secondpredetermined level.
 6. The multi-mode device of claim 5 wherein theelectrical characteristic comprises a resistance.
 7. The multi-modedevice of claim 6 wherein the mode detector circuit has an active modein which the mode detector circuit is configured to detect connection ofthe at least one of the second plurality of input/output connectors toan external device and a power save mode.
 8. The multi-mode device ofclaim 7 wherein, in the power save mode, the mode detector circuit isdisconnected from the at least one of the second plurality ofinput/output pads.
 9. The multi-mode device of claim 6 wherein thecontroller is configured to disconnect the mode detector circuit fromthe at least one of the second plurality of input/output pads in thesecond mode.
 10. A multi-mode integrated circuit device, comprising: acontroller configured to operate in a first mode compliant with theInternational Standard Organization (ISO) specification ISO 7816 and asecond mode different from ISO 7816 responsive to a mode selectionsignal; a first plurality of input/output pads associated withoperations in the first mode; a second plurality of input/output padsassociated with operations in the second mode; and a mode detectorcircuit coupled to at least one of the second plurality of input/outputpads and configured to detect connection of the at least one of thesecond plurality of input/output pads to an external device and toactivate the mode selection signal to select the second mode responsiveto detection of connection of the at least one of the second pluralityof input/output pads to the external device, wherein the mode detectorcircuit comprises: a reference current generator circuit coupled to theat least one of the second plurality of input/output pads; and aconnection detect circuit coupled to the reference current generatorcircuit and to the at least one of the second plurality of input/outputpads that activates the mode selection signal responsive to a detectionoutput signal from the reference current generator circuit and to asignal on the at least one of the second plurality of input/output pads.11. The multi-mode device of claim 10 further comprising a referencevoltage generator circuit that outputs a reference voltage to thereference current generator circuit and to the connection detect circuitand wherein the connection detect circuit activates the mode selectionsignal responsive to the reference voltage, the output signal from thereference current generator circuit and the signal on the at least oneof the second plurality of input/output pads.
 12. The multi-mode deviceof claim 11 wherein the controller is configured to generate a switchsignal in the second mode and wherein the mode detector circuit includesa switch circuit that disconnects the mode detector circuit from the atleast one of the second plurality of input/output pads responsive to theswitch signal.
 13. The multi-mode device of claim 11 wherein thereference current generator circuit comprises: first and second currentsource transistors, the current source transistors having current mirrorcharacteristics, the second current source transistor having an outputcoupled to a first input of the connection detect circuit and to the atleast one of the second plurality of input/output pads; a first resistorhaving a first node coupled to an output of the first current sourcetransistor and to a second input of the connection detect circuit; asecond resistor having a first node coupled in series to a second nodeof the first resistor; and wherein the connection detect circuit isconfigured to activate the mode selection signal responsive to a voltageat the first input of the connection detect circuit and a voltage at thesecond input to the connection detect circuit to select the second modewhen the resistance of the external device coupled to the at least oneof the second plurality of input/output pads is greater than aresistance of the second resistor and less than a sum of resistances ofthe first and second resistor.
 14. The multi-mode device of claim 13,wherein the controller is configured to generate a mode detection samplesignal and wherein the mode detector circuit is configured to activatethe mode selection signal responsive to detection of connection of theat least one of the second plurality of input/output pads to an externaldevice at a plurality of sequential times spaced at an interval definedby the mode detection sample signal.
 15. The multi-mode device of claim14 wherein the mode detector circuit further comprises a shift registercircuit clocked by the mode detection sample signal that activates themode selection signal after detecting connection of the at least one ofthe second plurality of input/output pads to an external device at aplurality of sequential times spaced at an interval defined by the modedetection sample signal.
 16. The multi-mode device of claim 13 whereinthe second mode comprises a Universal Serial Bus (USB) protocol mode.17. The multi-mode device of claim 13 wherein the reference currentgenerator circuit further comprises an amplifier having a first inputcoupled to the reference voltage signal from the reference voltagesignal generator, a second input coupled to the first node of the secondresistor and an output coupled to gates of the first and second currentsource transistors.
 18. The multi-mode device of claim 17 furthercomprising: a system bus coupled to the controller; an ISO interfacecircuit coupled to the system bus; a second mode interface circuitcoupled to the system bus; and a memory coupled to the system bus. 19.The multi-mode device of claim 18 wherein the memory comprises: a randomaccess memory (RAM) coupled to the system bus; a non-volatile memory(NVM) coupled to the system bus; and a read only memory (ROM) coupled tothe system bus.
 20. A smart card system comprising a USB adapter moduleand the multi-mode device of claim
 1. 21. A multi-mode integratedcircuit device, comprising: a controller configured to operate in afirst mode compliant with the International Standard Organization (ISO)specification ISO 7816 protocol and a second mode different from ISO7816 responsive to a mode selection signal; a first plurality ofinput/output pads associated with operations in the first mode; a secondplurality of input/output pads associated with operations in the secondmode, the second plurality of input/output pads including a firstvoltage input/output pad, a second voltage input/output pad and a datainput/output pad configured for a cable connection to communicate withan external device; and a mode detector circuit coupled to at least oneof the second plurality of input/output pads and configured to detect aresistance level of the external device when it is connected to the atleast one of the second plurality of input/output pads and to activatethe mode selection signal to select the second mode responsive todetection of a resistance level of the external device between a firstpredetermined level and second predetermined level.
 22. The multi-modeintegrated circuit device of claim 21 wherein the second mode comprisesa Universal Serial Bus (USB) mode.
 23. The multi-mode integrated circuitdevice of claim 22 wherein: the controller is further configured tooperate in a third mode compliant with an Institute for Electrical andElectronic Engineers (IEEE) 1394 protocol responsive to the modeselection signal; and wherein the mode detector circuit is configured togenerate a first value of the mode selection signal responsive todetection of connection of the at least one of the second plurality ofinput/output pads to a USB external device and to generate a secondvalue of the mode selection signal responsive to detection of connectionof the at least one of the second plurality of input/output pads to anIEEE 1394 device.
 24. A multi-mode integrated circuit device,comprising: a controller configured to operate in a first mode compliantwith the International Standard Organization (ISO) specification ISO7816 protocol and a second mode different from ISO 7816 responsive to amode selection signal and to generate a mode detection sample signal; afirst plurality of input/output pads associated with operations in thefirst mode; a second plurality of input/output pads associated withoperations in the second mode; and a mode detector circuit coupled to atleast one of the first plurality or the second plurality of input/outputpads and configured to detect connection of the at least one of thefirst plurality of input/output pads or the at least one of the secondplurality of input/output connectors to an external device at aplurality of sequential times spaced at an interval defined by the modedetection sample signal and to drive the mode selection signal to selectthe first mode or the second mode responsive to detection of connectionof the at least one of the first plurality of input/output pads or theat least one of the second plurality of input/output pads to theexternal device at the plurality of sequential times.
 25. The multi-modeintegrated circuit device of claim 24 wherein the second mode comprisesan Institute for Electrical and Electronic Engineers (IEEE) 1394protocol mode or a Universal Serial Bus (USB) protocol mode.
 26. Themulti-mode device of claim 25 wherein the mode detector circuit isconfigured to detect connection of the at least one of the firstplurality of input/output pads or the at least one of the secondplurality of input/output connectors to an external device by detectingan electrical characteristic of an external device connected to the atleast one of the first plurality of input/output pads or the at leastone of the second plurality of input/output pads to an external device.27. The multi-mode device of claim 26 wherein the mode detector circuitis configured to activate the mode selection signal responsive to theelectrical characteristic having a detected level between a firstpredetermined level and a second predetermined level.
 28. The multi-modedevice of claim 27 wherein the electrical characteristic comprises aresistance.
 29. The multi-mode device of claim 28 wherein the controlleris configured to disconnect the mode detector circuit from the secondplurality of input/output pads in the second mode.